[8u60] Request for Approval: 8129959: DebugLogger has unnecessary API methods

[Attila Szegedi]

Please approve.

Bug: https://bugs.openjdk.java.net/browse/JDK-8129959
jdk9 webrev: http://cr.openjdk.java.net/~attila/8129959/webrev.jdk9
jdk9 review thread: http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-June/004827.html

Changes apply cleanly to jdk8u-dev after path reshuffling from modular source code layout.

Thanks,
  Attila.